feat: Support JSON payload in HTTP requests (#213)

* Add support for setting Content-Type header to application/json

* Add support for serialization and deserialization of json payload

* Modified json ingress code changes with variadic functions

client/base_client.go

@@ -10,5 +10,5 @@ type BaseClient interface {
 	AccountSid() string
 	SetTimeout(timeout time.Duration)
 	SendRequest(method string, rawURL string, data url.Values,
-		headers map[string]interface{}) (*http.Response, error)
+		headers map[string]interface{}, body ...byte) (*http.Response, error)
 }

client/client.go

@@ -5,13 +5,13 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"bytes"
 	"net/url"
 	"regexp"
 	"runtime"
 	"strconv"
 	"strings"
 	"time"
-
 	"github.com/pkg/errors"
 	"github.com/twilio/twilio-go/client/form"
 )
@@ -56,7 +56,17 @@ func (c *Client) SetTimeout(timeout time.Duration) {
 	c.HTTPClient.Timeout = timeout
 }
 
+func extractContentTypeHeader(headers map[string]interface{}) (cType string){
+		headerType, ok := headers["Content-Type"]
+			if !ok {
+				return urlEncodedContentType
+			  } 
+			return headerType.(string)
+}
+
 const (
+	urlEncodedContentType = "application/x-www-form-urlencoded"
+	jsonContentType = "application/json"
 	keepZeros = true
 	delimiter = '.'
 	escapee   = '\\'
@@ -89,16 +99,24 @@ func (c *Client) doWithErr(req *http.Request) (*http.Response, error) {
 
 // SendRequest verifies, constructs, and authorizes an HTTP request.
 func (c *Client) SendRequest(method string, rawURL string, data url.Values,
-	headers map[string]interface{}) (*http.Response, error) {
+	headers map[string]interface{}, body ...byte) (*http.Response, error) {
+
+	contentType := extractContentTypeHeader(headers)
+
 	u, err := url.Parse(rawURL)
 	if err != nil {
 		return nil, err
 	}
-
+	
 	valueReader := &strings.Reader{}
 	goVersion := runtime.Version()
+	var req *http.Request
 
-	if method == http.MethodGet {
+	//For HTTP GET Method there are no body parameters. All other parameters like query, path etc
+	// are added as information in the url itself. Also while Content-Type is json, we are sending 
+	// json body. In that case, data variable conatins all other parameters than body, which is the 
+	//same case as GET method. In that case as well all parameters will be added to url
+	if method == http.MethodGet || contentType == jsonContentType{
 		if data != nil {
 			v, _ := form.EncodeToStringWith(data, delimiter, escapee, keepZeros)
 			regex := regexp.MustCompile(`\.\d+`)
@@ -108,13 +126,28 @@ func (c *Client) SendRequest(method string, rawURL string, data url.Values,
 		}
 	}
 
-	if method == http.MethodPost {
-		valueReader = strings.NewReader(data.Encode())
+	//data is already processed and information will be added to u(the url) in the
+	//previous step. Now body will solely contain json payload 
+	if contentType == jsonContentType {
+		req, err = http.NewRequest(method, u.String(), bytes.NewBuffer(body))
+		if err != nil {
+			return nil, err
+		}		
+	} else {
+		//Here the HTTP POST methods which is not having json content type are processed
+		//All the values will be added in data and encoded (all body, query, path parameters)
+		if method == http.MethodPost {
+			valueReader = strings.NewReader(data.Encode())
+		}
+		req, err = http.NewRequest(method, u.String(), valueReader)
+		if err != nil {
+			return nil, err
+		}
+
 	}
 
-	req, err := http.NewRequest(method, u.String(), valueReader)
-	if err != nil {
-		return nil, err
+	if contentType == urlEncodedContentType{
+		req.Header.Add("Content-Type", urlEncodedContentType)
 	}
 
 	req.SetBasicAuth(c.basicAuth())
@@ -128,14 +161,9 @@ func (c *Client) SendRequest(method string, rawURL string, data url.Values,
 
 	req.Header.Add("User-Agent", userAgent)
 
-	if method == http.MethodPost {
-		req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
-	}
-
 	for k, v := range headers {
 		req.Header.Add(k, fmt.Sprint(v))
 	}
-
 	return c.doWithErr(req)
 }
 
@@ -147,4 +175,4 @@ func (c *Client) SetAccountSid(sid string) {
 // Returns the Account SID.
 func (c *Client) AccountSid() string {
 	return c.accountSid
-}
+}

client/request_handler.go

@@ -23,13 +23,12 @@ func NewRequestHandler(client BaseClient) *RequestHandler {
 }
 
 func (c *RequestHandler) sendRequest(method string, rawURL string, data url.Values,
-	headers map[string]interface{}) (*http.Response, error) {
+	headers map[string]interface{}, body ...byte) (*http.Response, error) {
 	parsedURL, err := c.BuildUrl(rawURL)
 	if err != nil {
 		return nil, err
 	}
-
-	return c.Client.SendRequest(method, parsedURL, data, headers)
+	return c.Client.SendRequest(method, parsedURL, data, headers, body...)
 }
 
 // BuildUrl builds the target host string taking into account region and edge configurations.
@@ -83,8 +82,8 @@ func (c *RequestHandler) BuildUrl(rawURL string) (string, error) {
 	return u.String(), nil
 }
 
-func (c *RequestHandler) Post(path string, bodyData url.Values, headers map[string]interface{}) (*http.Response, error) {
-	return c.sendRequest(http.MethodPost, path, bodyData, headers)
+func (c *RequestHandler) Post(path string, bodyData url.Values, headers map[string]interface{}, body ...byte) (*http.Response, error) {
+	return c.sendRequest(http.MethodPost, path, bodyData, headers, body...)
 }
 
 func (c *RequestHandler) Get(path string, queryData url.Values, headers map[string]interface{}) (*http.Response, error) {